The principles of genetics are being used to change the world! Genetic Engineering The principles of genetics are being used to change the world!

Human Traits Remember: Human traits are inherited according to Mendel’s principles: Principles of Dominance and Segregation Pedigrees are used to study how traits are passed from one generation to the next. However, most human traits are impossible to trace as single genes. Remember: Many human traits are polygenic = many genes control a single trait Phenotypes are influenced by genotypes and the environment.

Figure 14-3 A Pedigree Section 14-1 Go to Section: A circle represents a female. A square represents a male. A horizontal line connecting a male and female represents a marriage. A vertical line and a bracket connect the parents to their children. A half-shaded circle or square indicates that a person is a carrier of the trait. A circle or square that is not shaded indicates that a person neither expresses the trait nor is a carrier of the trait. A completely shaded circle or square indicates that a person expresses the trait. Go to Section:

Human Genes The human genome includes tens of thousands of genes and the DNA sequence on these genes determines many characteristics. Gene mapping is the process of identifying the trait each gene is responsible for on each chromosome.

The Human Genome Project The Human Genome Project is an attempt to sequence all human DNA. In February 2001, scientists successfully mapped the human genome If your genome were a textbook, it would be 4 million pages long.

Bioethics and You As you become more aware of scientific advances in genetics, you might realize that with the ability to manipulate genes, there comes responsibility. This ability provides an opportunity to improve the lives of many people. But there is also a potential for errors or intentional misuse of the technology. Over the next week, think about this….. 1. In what type of situation do you think genetic engineering—changing the genes of organisms—is warranted? Explain your reasoning about your position. If you do not think that genetic engineering is ever warranted, explain your reasons for your position. 2. In what type of situation do you think genetic engineering might be misused? Suggest limits that might be placed on the manipulation of genes to avoid its misuse.

Selective Breeding Selective breeding, or artificial selection, is when people take control and cross organisms with selected traits. Humans use selective breeding to pass desired traits on to the next generation of organisms. For example, domestic dogs are bred for desirable physical characteristics and health traits. For example, most crop plants are crossed for desirable tolerances to temperatures and diseases.

Hybridization “Get a mutt, its healthier!” Hybridization = crossing dissimilar individuals to bring together the best of both organisms Hybrids = hardier individuals produced by hybridization.

Inbreeding “Pure bred dogs are just as healthy” Inbreeding = the continued breeding of individuals with similar characteristics One major problem: Inbreeding is more likely to cross two recessive alleles producing genetic defects.

What about Variation? Some scientists try to preserve the diversity in our world Other scientists try to increase the diversity in our world = more variation! Breeders can increase the genetic variation in a population by inducing mutations, which are the ultimate source of genetic variability!

Mutations Remember: Mutations are inheritable changes in DNA. You can wait for mutations to occur spontaneously, or you can increase the rate of mutations by using radiation or chemicals Mutations can be harmful or desirable to an organism!

Some Mutant Examples New Bacteria: Scientists have been able to develop hundreds of useful bacterial strains with mutations. For example, bacteria that digests oil and cleans water after oil spills New Plants: Scientists have been able to develop drugs that prevent chromosomal separate during meiosis in plants. For example, polyploid plants have many sets of chromosomes and are larger and stronger

This is all Genetic Engineering! Genetic engineering changes the arrangement of DNA that makes up a gene. Genes can also be inserted into cells to change how the cell performs. For example, large volumes of medicines, such as insulin, can be produced or plants resistant to diseases can be developed. Biotechnology is a branch of science studying genetic engineering and changing the way we interact with the living world.

Other Uses of Genetic Engineering In the past, people breed for organisms with desired traits by selective breeding, but now people can insert genes (DNA) into cells to produce organisms with those same desired traits by genetic engineering (Cell Transformation) Gene therapy is a form of genetic engineering that inserts a normal allele into a virus that attacks a target cell and inserts the normal allele into the body. Cloning is the process of making a new identical copy of an organism from a single adult cell. Cloning can occur naturally as twins, or to genetically engineer plants and animals, endangered or extinct species, a deceased pet or human, or stem cells. Stem cells are the cells that all of your cells “stem” from. Stem cells can be used to determine the function of specific genes, manipulate genes, or make new cells or tissue to treat injuries or diseases.